/*
 *  FIPS-180-1 compliant SHA-1 implementation
 *
 *  Copyright (C) 2006-2013, Brainspark B.V.
 *
 *  This file is part of PolarSSL (http://www.polarssl.org)
 *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
 *
 *  All rights reserved.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
/*
 *  The SHA-1 standard was published by NIST in 1993.
 *
 *  http://www.itl.nist.gov/fipspubs/fip180-1.htm
 */

#include "sha1.h"
#include "utils.h"

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n, b, i)                                                                                                                                                            \
	{                                                                                                                                                                                     \
		(n) = (static_cast<uint32_t>((b)[(i)]) << 24) | (static_cast<uint32_t>((b)[(i) + 1]) << 16) | (static_cast<uint32_t>((b)[(i) + 2]) << 8) | (static_cast<uint32_t>((b)[(i) + 3])); \
	}
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n, b, i)                                \
	{                                                         \
		(b)[(i)] = static_cast<unsigned char>((n) >> 24);     \
		(b)[(i) + 1] = static_cast<unsigned char>((n) >> 16); \
		(b)[(i) + 2] = static_cast<unsigned char>((n) >> 8);  \
		(b)[(i) + 3] = static_cast<unsigned char>((n));       \
	}
#endif

/*
 * SHA-1 context setup
 */
void sha1_starts(sha1_context* ctx)
{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xEFCDAB89;
	ctx->state[2] = 0x98BADCFE;
	ctx->state[3] = 0x10325476;
	ctx->state[4] = 0xC3D2E1F0;
}

void sha1_process(sha1_context* ctx, const unsigned char data[64])
{
	uint32_t temp, W[16], A, B, C, D, E;

	GET_UINT32_BE(W[0], data, 0);
	GET_UINT32_BE(W[1], data, 4);
	GET_UINT32_BE(W[2], data, 8);
	GET_UINT32_BE(W[3], data, 12);
	GET_UINT32_BE(W[4], data, 16);
	GET_UINT32_BE(W[5], data, 20);
	GET_UINT32_BE(W[6], data, 24);
	GET_UINT32_BE(W[7], data, 28);
	GET_UINT32_BE(W[8], data, 32);
	GET_UINT32_BE(W[9], data, 36);
	GET_UINT32_BE(W[10], data, 40);
	GET_UINT32_BE(W[11], data, 44);
	GET_UINT32_BE(W[12], data, 48);
	GET_UINT32_BE(W[13], data, 52);
	GET_UINT32_BE(W[14], data, 56);
	GET_UINT32_BE(W[15], data, 60);

#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define R(t)                                           \
	(                                                  \
		temp = W[(t - 3) & 0x0F] ^ W[(t - 8) & 0x0F] ^ \
	           W[(t - 14) & 0x0F] ^ W[t & 0x0F],       \
		(W[t & 0x0F] = S(temp, 1)))

#define P(a, b, c, d, e, x)                \
	{                                      \
		e += S(a, 5) + F(b, c, d) + K + x; \
		b = S(b, 30);                      \
	}

	A = ctx->state[0];
	B = ctx->state[1];
	C = ctx->state[2];
	D = ctx->state[3];
	E = ctx->state[4];

#define F(x, y, z) (z ^ (x & (y ^ z)))
#define K 0x5A827999

	P(A, B, C, D, E, W[0]);
	P(E, A, B, C, D, W[1]);
	P(D, E, A, B, C, W[2]);
	P(C, D, E, A, B, W[3]);
	P(B, C, D, E, A, W[4]);
	P(A, B, C, D, E, W[5]);
	P(E, A, B, C, D, W[6]);
	P(D, E, A, B, C, W[7]);
	P(C, D, E, A, B, W[8]);
	P(B, C, D, E, A, W[9]);
	P(A, B, C, D, E, W[10]);
	P(E, A, B, C, D, W[11]);
	P(D, E, A, B, C, W[12]);
	P(C, D, E, A, B, W[13]);
	P(B, C, D, E, A, W[14]);
	P(A, B, C, D, E, W[15]);
	P(E, A, B, C, D, R(16));
	P(D, E, A, B, C, R(17));
	P(C, D, E, A, B, R(18));
	P(B, C, D, E, A, R(19));

#undef K
#undef F

#define F(x, y, z) (x ^ y ^ z)
#define K 0x6ED9EBA1

	P(A, B, C, D, E, R(20));
	P(E, A, B, C, D, R(21));
	P(D, E, A, B, C, R(22));
	P(C, D, E, A, B, R(23));
	P(B, C, D, E, A, R(24));
	P(A, B, C, D, E, R(25));
	P(E, A, B, C, D, R(26));
	P(D, E, A, B, C, R(27));
	P(C, D, E, A, B, R(28));
	P(B, C, D, E, A, R(29));
	P(A, B, C, D, E, R(30));
	P(E, A, B, C, D, R(31));
	P(D, E, A, B, C, R(32));
	P(C, D, E, A, B, R(33));
	P(B, C, D, E, A, R(34));
	P(A, B, C, D, E, R(35));
	P(E, A, B, C, D, R(36));
	P(D, E, A, B, C, R(37));
	P(C, D, E, A, B, R(38));
	P(B, C, D, E, A, R(39));

#undef K
#undef F

#define F(x, y, z) ((x & y) | (z & (x | y)))
#define K 0x8F1BBCDC

	P(A, B, C, D, E, R(40));
	P(E, A, B, C, D, R(41));
	P(D, E, A, B, C, R(42));
	P(C, D, E, A, B, R(43));
	P(B, C, D, E, A, R(44));
	P(A, B, C, D, E, R(45));
	P(E, A, B, C, D, R(46));
	P(D, E, A, B, C, R(47));
	P(C, D, E, A, B, R(48));
	P(B, C, D, E, A, R(49));
	P(A, B, C, D, E, R(50));
	P(E, A, B, C, D, R(51));
	P(D, E, A, B, C, R(52));
	P(C, D, E, A, B, R(53));
	P(B, C, D, E, A, R(54));
	P(A, B, C, D, E, R(55));
	P(E, A, B, C, D, R(56));
	P(D, E, A, B, C, R(57));
	P(C, D, E, A, B, R(58));
	P(B, C, D, E, A, R(59));

#undef K
#undef F

#define F(x, y, z) (x ^ y ^ z)
#define K 0xCA62C1D6

	P(A, B, C, D, E, R(60));
	P(E, A, B, C, D, R(61));
	P(D, E, A, B, C, R(62));
	P(C, D, E, A, B, R(63));
	P(B, C, D, E, A, R(64));
	P(A, B, C, D, E, R(65));
	P(E, A, B, C, D, R(66));
	P(D, E, A, B, C, R(67));
	P(C, D, E, A, B, R(68));
	P(B, C, D, E, A, R(69));
	P(A, B, C, D, E, R(70));
	P(E, A, B, C, D, R(71));
	P(D, E, A, B, C, R(72));
	P(C, D, E, A, B, R(73));
	P(B, C, D, E, A, R(74));
	P(A, B, C, D, E, R(75));
	P(E, A, B, C, D, R(76));
	P(D, E, A, B, C, R(77));
	P(C, D, E, A, B, R(78));
	P(B, C, D, E, A, R(79));

#undef K
#undef F

	ctx->state[0] += A;
	ctx->state[1] += B;
	ctx->state[2] += C;
	ctx->state[3] += D;
	ctx->state[4] += E;
}

/*
 * SHA-1 process buffer
 */
void sha1_update(sha1_context* ctx, const unsigned char* input, size_t ilen)
{
	size_t fill;
	uint32_t left;

	// TODO:: Syphurith: Orz. It is said that size_t is an unsigned type..
	if (ilen <= 0)
		return;

	left = ctx->total[0] & 0x3F;
	fill = 64 - left;

	ctx->total[0] += static_cast<uint32_t>(ilen);
	ctx->total[0] &= 0xFFFFFFFF;

	if (ctx->total[0] < static_cast<uint32_t>(ilen))
		ctx->total[1]++;

	if (left && ilen >= fill)
	{
		memcpy(ctx->buffer + left, input, fill);
		sha1_process(ctx, ctx->buffer);
		input += fill;
		ilen -= fill;
		left = 0;
	}

	while (ilen >= 64)
	{
		sha1_process(ctx, input);
		input += 64;
		ilen -= 64;
	}

	if (ilen > 0)
		memcpy(ctx->buffer + left, input, ilen);
}

static const unsigned char sha1_padding[64] =
	{
		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/*
 * SHA-1 final digest
 */
void sha1_finish(sha1_context* ctx, unsigned char output[20])
{
	uint32_t last, padn;
	uint32_t high, low;
	unsigned char msglen[8];

	high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
	low = (ctx->total[0] << 3);

	PUT_UINT32_BE(high, msglen, 0);
	PUT_UINT32_BE(low, msglen, 4);

	last = ctx->total[0] & 0x3F;
	padn = (last < 56) ? (56 - last) : (120 - last);

	sha1_update(ctx, sha1_padding, padn);
	sha1_update(ctx, msglen, 8);

	PUT_UINT32_BE(ctx->state[0], output, 0);
	PUT_UINT32_BE(ctx->state[1], output, 4);
	PUT_UINT32_BE(ctx->state[2], output, 8);
	PUT_UINT32_BE(ctx->state[3], output, 12);
	PUT_UINT32_BE(ctx->state[4], output, 16);
}

/*
 * output = SHA-1( input buffer )
 */
void sha1(const unsigned char* input, size_t ilen, unsigned char output[20])
{
	sha1_context ctx;

	sha1_starts(&ctx);
	sha1_update(&ctx, input, ilen);
	sha1_finish(&ctx, output);

	mbedtls_zeroize(&ctx, sizeof(sha1_context));
}

/*
 * SHA-1 HMAC context setup
 */
void sha1_hmac_starts(sha1_context* ctx, const unsigned char* key, size_t keylen)
{
	size_t i;
	unsigned char sum[20];

	if (keylen > 64)
	{
		sha1(key, keylen, sum);
		keylen = 20;
		key = sum;
	}

	memset(ctx->ipad, 0x36, 64);
	memset(ctx->opad, 0x5C, 64);

	for (i = 0; i < keylen; i++)
	{
		ctx->ipad[i] ^= key[i];
		ctx->opad[i] ^= key[i];
	}

	sha1_starts(ctx);
	sha1_update(ctx, ctx->ipad, 64);

	mbedtls_zeroize(sum, sizeof(sum));
}

/*
 * SHA-1 HMAC process buffer
 */
void sha1_hmac_update(sha1_context* ctx, const unsigned char* input, size_t ilen)
{
	sha1_update(ctx, input, ilen);
}

/*
 * SHA-1 HMAC final digest
 */
void sha1_hmac_finish(sha1_context* ctx, unsigned char output[20])
{
	unsigned char tmpbuf[20];

	sha1_finish(ctx, tmpbuf);
	sha1_starts(ctx);
	sha1_update(ctx, ctx->opad, 64);
	sha1_update(ctx, tmpbuf, 20);
	sha1_finish(ctx, output);

	memset(tmpbuf, 0, sizeof(tmpbuf));
}

/*
 * SHA1 HMAC context reset
 */
void sha1_hmac_reset(sha1_context* ctx)
{
	sha1_starts(ctx);
	sha1_update(ctx, ctx->ipad, 64);
}

/*
 * output = HMAC-SHA-1( hmac key, input buffer )
 */
void sha1_hmac(const unsigned char* key, size_t keylen,
	const unsigned char* input, size_t ilen,
	unsigned char output[20])
{
	sha1_context ctx;

	sha1_hmac_starts(&ctx, key, keylen);
	sha1_hmac_update(&ctx, input, ilen);
	sha1_hmac_finish(&ctx, output);

	memset(&ctx, 0, sizeof(sha1_context));
}
